


throne's verse

by armethaumaturgy



Series: Reqs [11]
Category: Undertale (Video Game)
Genre: Blow Jobs, Breast Fucking, Cross (X-tale) - Freeform, Crossmare - Freeform, Ecto-Genitalia (Undertale), Explicit Sexual Content, M/M, Mating Cycles/In Heat, Multiple Orgasms, Nightmare (Dreamtale) - Freeform, Overstimulation, Rutting, Tentacle Sex, cross/nightmare - Freeform
Language: English
Status: Completed
Published: 2021-03-11
Updated: 2021-03-11
Packaged: 2021-03-18 04:48:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,027
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29977620
Author URL: https://archiveofourown.org/users/armethaumaturgy/pseuds/armethaumaturgy
Summary: "Something on my face?" Cross asked, and his chuckle sounded a bit strained this time.Nightmare didn't answer for a second. His tentacles were no longer idle, instead flicking minutely, coiling their tips into themselves. "No," he said finally, "I just thought we could have some fun together."
Relationships: Sans/Sans (Undertale)
Series: Reqs [11]
Series URL: https://archiveofourown.org/series/2151672
Comments: 2
Kudos: 124





	throne's verse

**Author's Note:**

  * For [NeahChanArt](https://archiveofourown.org/users/NeahChanArt/gifts).



> written for @NeahChanArt on twitter! ♥♥

The doors to the throne room were large, ornate in their carvings. Even the faded layer of patina only made it look more majestic.

Cross had seen those doors before, of course. Countless times, in fact. But they always pulled his attention, the engraved symbols and claw marks like a magnet for eyes. It was designed that way, probably, but knowing that still didn't stop Cross from marveling at it. Or maybe he was simply stalling, prolonging the inevitable while his nerves settled.

"Coming in, boss," he announced, pushing the heavy brass doors open. They squeaked on the hinges and let the light from the hallway torches illuminate the long carpet leading up to the throne.

Nightmare sat on it, draped sideways with a book in his hands, tentacles lazily flicking behind him. He made for the perfect picture of royalty like that; all that was missing was a crown on his head. Cross wasn't sure why he sometimes read in the study, sometimes in the library, and other times in here, but he looked most fitting in this vast room. In Cross' opinion, anyways.

His piercing eyelight lifted from the lines of ink and settled on Cross, and the quirk of his teeth was unmistakable.

"That was quick," he said, unheedingly folding the corner of the page he'd left on. A tentacle moved the book somewhere into the shadows, where the meager light didn't hit. 

"Yeah," Cross chuckled, fidgeting a bit as he remembered that nagging feeling of longing that wasn't quite his own earlier. "Came as soon as you called."

"Is that so," Nightmare muttered, nothing but an idle thought as he kept staring at Cross. His fidgeting got worse.

"Something on my face?" he asked, and his chuckle sounded a bit strained this time.

Nightmare didn't answer for a second. His tentacles were no longer idle, instead flicking minutely, coiling their tips into themselves. "No," he said finally, "I just thought we could have some fun together."

Cross looked off to the side, hating that the implications of the words were making magic rush up to his cheeks. Whenever someone in the castle mentioned 'fun', it was a coin toss between sex and homicide. Cross was not above admitting both of them were appealing in their own way. However, with Nightmare's tone, he could infer which one it was.

"Come here," his boss beckoned, when he took a moment too long just standing there for his tastes.

He did, steps light on the plush carpet as he walked up to the throne. He was taller than Nightmare, a fact that didn't make up for the difference in their strengths, but did something to Cross' mess of a SOUL when he saw just how far he towered over the corrupted skeleton like this. And there was something else, too...

From this close up, the scent was unmistakable. It clung to Nightmare like the most expensive of perfumes, heady and thick in the air, and Cross' eyelights dilated. Heat. It was the scent of heat.

"Boss..." Cross started, unsure himself where he was going with it, but once he trailed off, it didn't matter much. 

Nightmare looked up at him. He didn't seem affected, save for the slight fuzziness to his eyelight, and it spoke volumes of his self-control. To be this far into a heat and stay as cohesive -- he'd been reading a book, for stars' sake! -- as he was, was nigh unheard of. He stood up, displacing the air and only making the scent that much more obvious.

"Objections?" he asked, quirking a browbone.

"N-no," Cross replied, immediately, and cursed the stutter in his voice. His bones felt warm, itchy under his skin. Belatedly, he realized it had been an out, Nightmare's way of saying he wouldn't take what wasn't freely given. But when had Cross ever refused him what he wanted?

"Good," his king all but purred. Cross' SOUL jumped at the appreciation in his voice, giddy as ever for it; he couldn't even blame it on the scent, not when it was a constant with him. No doubt, Nightmare could tell, though he never said anything about it.

A tentacle wound around his wrist, and Cross was about to ask what he should do, but instead all that left him was a yelp, vertigo overtaking his mind as he was spun. He found himself in Nightmare's spot, held down on the throne while the other stood above him.

He struggled half-heartedly against the now-pair of tentacles pinning his arms to the armrests. It didn't feel correct to sit on the throne, even if he had entertained fleeting curiosity about it. The plush cushions were infinitely more comfortable than he could've thought.

"Boss?" 

Nightmare's lopsided grin returned, and when he sat himself onto Cross' lap, he could feel the heat of him even through the layers of clothing. If he felt warm, Nightmare felt like he was burning up from the inside. He didn't get too long to be concerned about it, not when Nightmare leaned up and slotted their teeth together, a little too fast and hard, but it seemed to be everything he'd ever wanted.

Nightmare's body relaxed against Cross, and only then did the previous tenseness become apparent. Silly, Cross thought of himself, for thinking Nightmare wouldn't be affected by his own heat, no matter how good he was at controlling himself.

His hands were still held down, and he couldn't do anything, couldn't touch like he wanted to. He couldn't even protest with the way Nightmare's tongue tangled with his, swallowing up any and all noises between them.

He was left breathless as Nightmare pulled away, a string of saliva connecting them, snapping as Nightmare moved down his body, but not before allowing himself a rough grind against Cross' pelvis, pulling a hissed groan out of both of them. Cross watched as he settled on the floor, licking the magic off his teeth and looking up at him. It was all Cross could do to keep the eye contact.

Nightmare's hand wasted no time in pulling his shorts down, only making Cross' blush worse when the swirling pool of magic that had already gathered in his pelvic inlet was revealed, casting a soft glow on the corruption dripping down Nightmares face. Nightmare dipped right into, fingers teasing at the edges of the cloud, clever wrist flicks having sparks exploding behind Cross' eyelights.

"How are you going to please me?" Nightmare asked, pulling Cross' attention back to himself. His magic yearned to manifest, charged and bright, but he forced himself to look at Nightmare instead of letting it, noticing the faint cyan peeking from under his sweater.

"What... would you like, boss?"

Nightmare's eyesocket narrowed. "Make a cock, Cross."

Cross shuddered at the tone, the command going straight to the pool of magic Nightmare had stopped teasing, and it was, embarrassingly, enough to have him do as Nightmare wanted, his body manifesting with an audible crack of the magic. Immediately, Nightmare had a hand around his cock, phalanges gliding over the fake flesh with ease. His corruption always made everything smoother, and Cross couldn't find the words to show his appreciation, so he let his hips do it for him, arching up into the touches.

"Wasn't so hard, now was it?" Nightmare muttered, as if to himself. He leaned in and dragged the flat of his tongue across the purple length, and Cross gasped out a groan at the hot touch. 

Nightmare's teeth parted and he took the cock into his mouth, letting Cross feel just how heated he truly was. The space between his tongue and the roof of his mouth was like a furnace, tempting him to shove further in.

But Nightmare pulled off, entirely too early, even if Cross was already finding himself teetering on the precipice of an orgasm from so little.

"Stars, you sound like  _ you're  _ the one in heat," Nightmare muttered. His fingers were stroking the dick, idly. Only when he'd mentioned it did Cross realize he'd been panting, his breathing labored and stuttering. 

"Can't help it... boss," he ground out, the pseudo-muscles in his stomach tensing. Nightmare's finger was digging into the slit of his cock, small circles that ignited his whole body with tremors.

"Obviously. That's why I'm going to gag you."

Cross blinked his sockets open, looking down at Nightmare. There was a tentacle hovering in front of his mouth, but it waited half a SOULbeat before it plunged into his mouth. For all of Nightmare's talk of using them as nothing but pawns, all of them, he was a touch too caring. Cross decided he wouldn't mention it, not fancying the idea when Nightmare's teeth were still as close to his cock.

The tentacle filled his mouth, its tip breaching down to his throat, and reflexive tears sprung to the corners of his eyesockets despite the lack of a gag reflex.

Satisfied when Cross' noises were reduced to muffled groaning, Nightmare leaned back on his haunches and pulled his sweater off, shirt following soon after. The cyan magic took shape, and Cross' gaze slid down to his bosom, the way his breasts bounced as he adjusted to lean back in. Nightmare's tongue returned to his cock, licking at the head as his hands moved to his breasts, lifting them and... Oh, Cross whined around the tentacle.

Nightmare's boobs were just as hot as the rest of him, bracketing Cross' cock in-between them. The corruption dripped down from his neck, slowly but surely coating the cyan magic, and providing sweet friction as he started moving them, in time with his licking.

Cross cried out, nothing but a choked sound, as his body seized. Nightmare closed his socket as strips of purple landed on his face, the debauched look only serving to make Cross feel more heated.

"Are you that affected?" Nightmare asked, and it might have been rhetorical, but Cross tapped at the armrest with a numb phalanx.

The tentacle pulled out from his mouth, letting him gasp in a breath, Nightmare's browbone raised in inquiry as he got himself back in control at least a bit.

"Lemme... Lemme touch, Nightmare," he begged, voice strained and ruined.

The tentacle plunged right back, cutting off Cross' startled cry, but the ones holding his arms down unwound.

He made a noise, hoped it came across as the thanks he meant it as, and reached down, his hands replacing Nightmare’s own on his breasts. Nightmare’s mouth engulfed the head of his cock again, taking it as Cross’ hips stuttered, nerves half-friend from his orgasm. The sight alone would’ve been enough to get Cross off another time.

He kneaded at the supple ecto-flesh, and felt more than heard Nightmare’s moan, vibrating through him. His fingers passed over where his nipples were, digging into the shallow slits and scraping against the sensitive nubs. His reward was an arch of Nightmare’s spine, pressing his chest closer.

Over the slurping, he could only barely make out wet squelching, and with the tentacle now down his throat, he couldn’t even tell Nightmare how fucking  _ good _ he looked right then. There was a tentacle fucking into his cunt, his shorts bunched down around his knees to give it space.

Cross teased at Nightmare’s nipples, rolling them around to coax them out so he could tease them properly. Nightmare was moaning around his cock, hips bucking minutely as he fucked himself. Stars, the carpet would be ruined, wouldn’t it?

Eventually, with enough pinches and rubs, he had coaxed one of the nipples out, and Nightmare had to pull off his cock to moan as Cross tugged at it. He was still moving his boobs over his length, wondering just how hot his cunt had to be if this was how scalding the  _ outside _ of his ecto felt.

Nightmare was bracing himself against the throne, skull resting in the crook of Cross’ hip and thigh as he shook with shocks of pleasure. Cross tried to time his pinches with the tentacle’s pace, chalking Nightmare’s loud keep up to a victory.

“Cross…” Nightmare sighed, eyelight completely fuzzy as he gazed up, half-lidded. If Cross’ cock throbbed at the sound of his voice, it was just between the two of them.

Cross moved his foot, wedging it between Nightmare’s legs, and that cyan eyelight fell shut completely as the next thrust of the tentacle pushed him against Cross’ boot, pressure right against his clit.

If this were any other time, he was sure Nightmare would have scoffed and remarked how gross that was, but it  _ wasn’t _ any other time. He swallowed Cross’ cock down, as far as he could with his breasts in the way, body moving along with the pace he’d set for himself, fast and deep.

Cross could feel him shaking, the way he lingered forward for just a second each time, grinding against his foot like he couldn’t get enough.

With a couple tugs and pinches to his nipples, he had Nightmare choking on his cock, body tensing. He could hear the slick spattering the floor, even if he couldn’t  _ see _ it. Nightmare’s teeth skirted his cock and Cross came right along with him, Nightmare drinking his cum down like a man starved.

His bones were starting to crackle along the joints as he was licked through the release and straight into oversensitivity, but Nightmare only pulled away once he was sure he’d milked Cross for all he could give this time.

A mixture of cum and spit dripped down his mandibles, licked away by that sinful tongue. His boss stood on shaky legs, his tentacles assisting him in pulling the shorts off the rest of the way, and hunched as he still was, Cross could see the mess of cyan and black left on the carpet where he’d been kneeling. It was gross, it was  _ hot, _ and Cross’ body yearned for  _ more. _

It must’ve shown on his face, because Nightmare chuckled, the sound strained as it left him, and climbed onto the throne, knees braced on either side of Cross’ hips.

“Painted me inside and out,” he said, hands on his shoulders for stability. He looked like he wanted to kiss Cross, let him taste himself on his tongue, but he couldn’t with the tentacle still fucking his mouth, and he didn’t seem too keep on pulling it out just yet. “Now you better paint me again, this time  _ properly.” _

It was all the warning Cross got before Nightmare lowered himself onto his cock, skull thrown backwards with a moan that echoed through the whole throne room. His insides were hot like molten lava, clenching down on Cross like they never wanted to let him go.

“Ah,” Nightmare moaned again, shifting himself over Cross to get better leverage. His tentacles braced him from behind and he lifted himself onto to drop down, Cross’ cock hitting to the very back of his passage. “F-Finally…”

Cross’ own moan didn’t made it past the tentacle, hands gripping the armrests as his pseudo-nerves burned with the onslaught of pleasure. Nightmare leaned down and ran his mouth over his neck, nosing his hood away for easier access. He almost sobbed once his teeth bit down on one of the vertebrae.

“Touch me, Cross,” Nightmare commanded, and Cross’ hands found themselves on his breasts again, digging into the too-big mounds. His thumbs returned to teasing at his nipples and Nightmare made an appreciative groan, hips rolling against Cross’ before he started to bounce himself again, properly this time.

The pace he set was altogether too fast for Cross to keep up with; he couldn’t even lament the loss of his heat before it was back, his walls rubbing over Cross’ length like a velvety vice, squeezing down even tighter once Nightmare found an angle he enjoyed.

White spots danced in Cross’ vision, body and magic wound in a tight coil. His hands were shaking from all the sensations, but Nightmare seemed to enjoy the way he sometimes pinched his nipple harder than he’d intended to, if the way he jutted his chest into the touches was anything to go by.

The coil wound tighter and tighter, and Cross tried to warn Nightmare, but the warbled, choked noise was about as close to words as he was to being calm. Nightmare’s hips slammed down on him and it snapped, Cross’ whole body shaking as he came again, filling up Nightmare’s smaller frame until there was a slight bulge between them, barely visible under the corruption that coated Nightmare’s ecto-body.

Nightmare’s insides clenched, knees clicking against the throne as he sunk his teeth deeper into Cross’ neck, spattering the throne in cyan.

The tentacle finally pulled out of Cross’ mouth, letting him cough, jaw aching from being stretched for so long. His whole body felt leaden, and he was sure he would pass out any second. Nightmare slipped off of him, cyan and purple gushing out of him to add to the mess beneath them, and even that little bit of stimulation had tears gathering at the corners of Cross’ sockets.

“I’d call that fun. You are dismissed, Crossy,” Nightmare said, tentacles flicking while Cross put meaning behind the words, and eventually nodded. He almost fell over when he stood up. One of Nightmare’s tentacles pulled his shorts up and let him hold it as he stumbled his way out of the throne room. “Make sure to tell Dust I’ve called him if you see him first. He’s been ignoring me for a while now.”

Cross nodded again, not quite sure what the hell Dust had to do with—  _ oh. _ Cross couldn’t even muster enough energy to feel embarrassed.

Nightmare was in heat, he reminded himself. Of course a couple rounds wouldn’t be enough to satisfy him, even if he appeared completely fine, save the way his tentacles writhed as if they had a mind of their own.

He did not run into Dust on his way to his room.

He did, however, bump into Killer, and that was a whole 'nother can of worms that he would pay for later, when he was a bit more lucid.

**Author's Note:**

> my twitter is @esqers ♥


End file.
